In the fields of space technology and navigation guidance systems, it becomes necessary to process data from synchro and resolver sources with considerable speed and precision. The outputs from these synchros or resolvers may comprise n dimensional analog derived pointing vectors through angles derived from the shaft rotation of the resolvers or synchros.
The most common method of solution employs a servo-mechanism to position a computing resolver to be dictated by the external synchro source. One resolver, and often as many servos, are required for each coordinate transformation (i.e., to compute in the form X'=X Cos .theta. + Y Sin .theta. and Y' = Y Cos .theta. - X sin .theta.). The resolvers are electrically interconnected to provide the desired transformations and the total number of rotations of vector pairs to go from the initial system to the final system. Another solution involves digital computers in conjunction with analog-to-digital and digital-to-analog input/output terminal devices which are used where large amounts of digital storage is available or where costs permit. The computing methods for these digital devices commonly utilize conventional trigonometric subroutines requiring relatively large digital storage, noting that the digital storage requirements are proportional to the number of transformations. A third solution to the problem is the implementation of various solid state techniques. However, the past solid state techniques have been characterized by slow solution time and/or accuracy of solution which has been relatively poor.
The disadvantages attendant upon the above-mentioned solutions are substantial. The conventional servoed computing resolver chains have the disadvantage in that their moving parts are subject to wear and breakdown and thereby compromise reliability. They also require relatively short periods between preventive maintenance procedures and are bulky and heavy. Moreover, they have limited accuracy, comsume large amounts of power and are not easily adaptable to new applications. Conventional digital computers have the disadvantage in that digital computation requires high resolution to minimize truncation errors, large memory allocation, and are relatively slow as well as being prohibitive in cost.
The present invention overcomes the aforementioned disadvantages of the prior art. It provides high reliability through the use of solid state modules. It also has the advantages of easy maintenance and no requirement for calibration and alignment. Additional advantages are reduced weight, volume and power. Other advantages are low cost, timesharing capability and a minimum number of instruction and routines. Further, there is no need for extensive computing architecture because arithmetic means is exclusively iterative steps of shift and add.